The aim of this investigation is to identify the receptors which are activated as left ventricular dysfunction (LVD) evolves. It is likely that activation of pulmonary receptors contributes to the symptoms associated with LVD such as wheezing and rapid respiration. Sensory information from the lung is conveyed to the brain by four groups of vagal receptors (1) the slowly adapting receptors (SAR), (2) Rapidly adapting receptors (RAR), (3) Bronchial C and, (4) Pulmonary C fibers. Over the next 5 years, specific hypotheses relating to the following groups of experiments will be tested. I) Effect of acute small changes in Starling forces on sensory receptor subtypes in the lung II) Effect of acute-on-chronic changes in the Starling forces on the activity of pulmonary receptors III) Effect of activating the pulmonary receptors upon renal function IV) Effect of activating the pulmonary receptors upon respiratory rate, tidal volume and airway resistance Pulmonary receptors will be activated by obstructing lymph drainage from the lung. V) Effect of changing Starling forces in the lung on the distribution of interstitial fluid in the lung These experiments will define the nature of the microvascular disturbance created by the stimuli which activate the receptors. VI) Histological studies These studies will identify the distribution of vagal sensory receptors in the tracheobronchial tree. Sensory endings will be identified on the basis of silver staining of myelinated axons, degenerative changes in the nerve endings following cervical vagotomy and the presence of diamines following injections of horse radish peroxidase into the nodose ganglion.